The mother, Heather Jensen, told investigators that she took her sons to play in the snow near the Powderhorn Ski Resort on November 27. Then, she allegedly put them into the car while she spent time talking with her friend in his car.

After Heather Jensen returned to her Toyota 4 Runner to drive off, she noticed one of the boys was not breathing.

Paramedics could not revive 2-year-old William. The older son, Tyler, was airlifted to Children's Hospital, but he died several days later. First responders initially thought the kids may have suffered carbon monoxide poisoning, however the coroner's investigation found otherwise.